but I have problems setting CPU voltage and FSB. I think I have problems getting 400Mhz FSB.

I can run stable 1.3v (in BIOS, 1.24v in CPUZ) for 355x9, which is 3.2g (idle at 39C)and I can run stable 1.35v (in BIOS, 1.28v in CPUZ) for 365x9, which is 3.29g (idle at 42C)366~375 seems to fall into FSB holes. i tried 366x9, 370x9, 375x9, but they won't post. I think I will just skip those and go direct too 400x9

But when i do 400Mhz FSB, setting CPU to 1.5v in BIOS (1.44v in CPUZ) for 400x9, I can boot up, but system will crash to BOSD very soon.

I start to raise voltage to 1.5625v (1.48v in CPUZ), and still getting BSOD.

Should I keep increasing the voltage? Or my CPU won't get 3.6g no matter what? I see in other people's setting, the are getting 3.6g at below 1.5v voltage.

I know there is really not big difference in 3.6 and 3.29, but I really like to get 3.6g, it is like an overclocker's dream.

what you mean by +10%? is it the highest voltage i should go is 1.325 + 1.325x10% = 1.4575v in CPUZ? that will make around 1.5v max in BIOS.

I am monitoring the temperature closely. The first thing I will do if it boot up is open HWmonitor and check temperature. I believe in the unstable boots, it is like 55CLooks like I won't get 3.6g if that's the case.

have you remembered to play with the ram frequency ratio? maybe your ram is clocked too high. i have the same vid as you, and with my dfi i just overvolted the cpu by +250mV in teh bios and set my memory frequency ratio to 1:1 and i had no problems.

what cooler are you using and what software to monitor them. With good cooling you should reach 3.9 at 9X multiplier. But at that speed the processor is very sensitive to high temps. I would say your cpu is overheating. Also try 2.1v on your RAM

First of all, you have to decide which you want to overclock first, overclocking both your CPU and Memory at the same is bad overclocking habit. Make it so your memory is well below the spec'd 400MHZ, then slowly crank up your PROC making sure your memory is absolutely NOT getting OC'd, find the max CPU overclock. Now, underclock your proc and overclock your memory. Then set both when you find the threshold for each. I have my Q6600/G0/SLACR to 3.6 on air with 1.3875V. AGAIN, overclocking both CPU/MEM at the same time is a bad idea, you don't know which is at it's threshold, COME ON PEOPLE, NO ONE MENTIONED THIS. WOW, FFS.

1.5v on the cpu may not be enough to run 3.6ghz. After vdrop and vdroop, most q6600s in that vid range need about 1.44-1.46v to run stable. If you're still not getting it at 1.56+, you're cpu either isn't capable, or something else is holding you back.

Try these things. The FSB and GMH will both require more voltage. Start by overvolting them by .1v, and work your way up. Not more than +.3v. Relax the RAM timings to 6-6-6-18 3t until you get a stable clock. Measure the Vdrop an Vdroop, and figure out what voltage you need in the bios, to produce a vcore of ~1.46v under load. And, try setting up at 400X8 or 400x7 to make sure your mobo is capable of even running FSB 1600.

The only other factor I can think of is your power supply. I assume you have a decent unit, but if not, that could be the culprit.

Again, what software are you using to read temps? It's possible that your temps are higher than you think. You need an almost top of the line air cooler to reach 3.6 on a Q6600 and doubt a rosewill is, so my guess is your software is reading the temps wrong. Try coretemp (the newest version) it's free and very reliable.

"The Rosewill RCX-Z4 is not a heatsink for those looking to squeeze the last MHz out of an overclocked CPU. The benchmark numbers actually show that this product is not much better than the two factory coolers, but what do benchmarks really tell us besides the extreme ends of the scale."

I would say for sure the temps are too high for your cpu to handle. I have a better cooling solution and can't get past 3.45. If you want 3.6 look for a TRUE or the new ones with direct touch technology (from kwing, OCZ, etc.)

you can't dudge the roswill-z4 by reading the reviews. those review of the rosewill heatsink is not true. I have another cooler which is said to be top of the line, Scythe NINJA, huge heatsinks, but it is the rosewill beats it.

just confirmed, the tempereature reading from core temp and hardware monitor is exactly the same.

Well, in that case I don't know what to tell you. Your CPU should be able to handle almost 70ºC being stable. I can only suggest you do your overclock step by step as w153r and clownbaby said. At the exact point where you get an unstable cpu raise voltages, when stable again, continue with upping the FSB and so on.

I think it is the ram. in CPUZ, I read it 1.8v, while i set in BIOS 2.0v. I really need it to read 2.0v in CPUZ. I read from hardware.info, it can handle 2.35v. So I can push the ram voltage and see if it give me 3.6g.

It could be the problem, try 2.2v (I wouldn't go over 2.3v) also make sure you have the latest BIOS and always remember to go step by step. And if you have 4x1GB, you could try with only two until you are stable.

I also Doubted you could get 3.6GHZ with that cooler, but that doesn't mean you cant try 3.4 or something like that. That, of course, if you think it's worth the time spent and performance gain. Remember a 3dmark06 is basically a graphics test so you will gain much more by OC your graphics card than your CPU (which won't do much difference being a Quad).